An economics book is Amazon's top seller

'Capital in the Twenty-First Century' written by Thomas Piketty is not a quick read but is definitely flying off the shelves at Amazon.

The 685-page book has been translated from French and the reviews are "truly superb," as Paul Krugman called it in the New York Review of Books. The book talks about issues that are relevant to Americans, including income inequality.

"As economic growth slows in a country, the income generated by wealth balloons compared with income generated by work, and inequality skyrockets," Jordan Weissmann of Slate writes, adding that Piketty is probably "the most important thinker on inequality of the past decade or so."